I had just figured out my problem and was checking back on this thread.
I’m using Multi-DB and am putting the bbpress tables in the global database that Multi-DB requires. I also had to update BBDB_NAME to point to the global db. In this setup, the db settings in wp-config.php are being overriden apparently by db.php, db-config.php (Multi-DB). I only needed to update bb-config.php (for BBDB_NAME).
